Process for preparing lubricating oil dyes



sept. s, 1942.

Filed May 20.

G. R. GILBERT ETAL PROCESS Fon PREPARING LUBRICATING OIL DYES l 'FLUX/N G soLvEA/r SoLvENT EXTRAQT ESOL VENT/2ER D CNCENTRA TE Patented Sept. 8, 1942 PROCESS Fon PREPAmNG LUBmcA'ri'NG on. mms

George R. Gilbert and Albert A. Peer, Baytown, Tex., assignors to Standard Oil Development Company, a corporation of Delaware Application May 20, 1939, Serial No. 274,673 v 7 Claims. Cl. 19d-13) /The present invention relates to an improved lubricating oil dye suitable for imparting desirable blooms to petroleum lubricating oils. The dye of the present invention is produced from petroleum oil and will impart a desirable cast to petroleum lubricating oils without producing undesirable detrimental eiects on other properties.

Various procedures have been disclosed for the preparation of various dyes suitable for imparting various blooms to petroleum oils. The dyes heretofore secured have been satisfactory inso far as their dyeing properties are concerned.

However, in most instances it has been necessary to add a relatively large amount of the dye to secure the desired cast which results in an excessive increase in carbon residue and an increase in the Sligh numberpf the petroleum oil to which it has been added.

We have now discovered a process of producing a concentrated dye which, when used in small proportions, will impart a desirable cast to th'e petroleum oil. The dye produced by our invention moreover will improve the pour characteristics lof the oil and will also act as a cloud inhibitor. The process of producing the dye of the present invention may be readily understood by reference to the attached diagrammatical drawing illustrating one modification of the same.

A petroleum oil preferably boiling in the range between 260 F. and 540 F. and having a gravity in the range between`38 A. P, I. and 43 A. P. I. is introduced into solvent treating unit i by means of feed line 2. In solvent treating unit i the oil is contacted with a selective solvent selected from the class of solvents which have a preferential selectivity for the more aromatic type hydrocarbons as compared to the more parainic type hydrocarbons. Solvents of this class are, for example, phenol, furfural,k sulfur dioxide, cresci, nitrobenzene, aniline, beta beta dichlor diethyl ether and the like. For the purposes of illustration, it is assumed that'the oil l ity in thev range from about 1 A. P. I. to 6 A. P. I.

The cracking coil tar is removed from cracking unit 8 by means of line 9 and introduced'into unit IB in which the tar is deasphalted by means ef a deasphalting solvent which is introduced into unit l0 by means of line i l. .For the purposes of illustration, it is assumed that the deasphalting solvent is kerosene. The asphalt is removed by means of line l2 while the kerosene extract is removed by means of line I3 and introduced into desolventizer I4. Kerosene is removed from the deasphalted tar by means of line i5. The deasphalted tar is introduced into uxing unit i6 by means of line l1. A suitable uxing petroleum oil is then introduced into unit I6 by means of line I8 and the mixture removed by means of line I9 and introduced into treating unit 20. A solvent of the class of solvents having a preferential selectivity for the more aromatic type compounds as compared to th'e more paramnic type compounds, as for example, phenol, is introduced into solvent treating unit 20 by means of line 2| under conditions to form a solvent extract phase and a rainate phase. The solvent extract phase is removed from treating unit 20 by means of line 22 while the rainate phase is removed by means of line 23 and introduced into desolventizer 24m The phenol is removed from the rainate and light oil in desolventizer 2li and recycled to line 2l by means of. line 25. The solvent-free raffinate and light oil are then introduced into distillation unit 26by means of line 2l in which the light oil is removed by means of line 29. The dye concentrate of the present invention is removed from distillation unit 26 by means of line 28.

The process of the present inventionmay be widely varied. Any cracking coil tar is satisfactory which has a gravity in the range between 1 A. P. I. and 6 A. P. I. However, it is preferred that the cracking coil tar be produced from a cracked solvent extract, preferably a cracked sulfur dioxide extract, and that the tar have a gravity of about 2 A. P. I. to 3 A. P, I.

The heavy tar may be deasphalted in any suit, able manner by the use of light kerosene or by the use of liquefied normally gaseous hydrocarbons, as for example, propane, butane and the like. In general, it is preferred to deasphalt the tar by adding approximately of a deasphalting solvent such as light naphtha, propane or the like. The temperature and pressure conditions may vary Widely and are adjusted to secure optimum operation. In general, atmospheric temperature and a pressure sufficient to maintain the deasphalting solvent in the liquid state are' preferred. v

The deasphalted tar, after removal of the deasphalting solvent, is then fluxed with a suitable petroleum oil. It has been found that desirable results are secured if the deasphalted tar is fluxed with a paraiiinic light petroleum oil having a v gravity in the range from about 27 A. P. I. to 40 A. P. I. The iiuxed tar is then treated, preferably with phenol, under conditions to form a solvent extract phase and a rafnate phase. The rainate phase is separated from the solvent extract phase and treated in any suitable manner to remove the selective solvent. The solvent-free oil comprising the light iiuxing oil and the dye is then treated in a manner, preferably by distillation, to remove the light oil. The distillation operation is preferably conducted under vacuum at an absolute pressure from about 1 mm. to 10 mm. and at a temperature not exceeding about 500 F. to 650 F. in order to prevent decomposition of the dye. The dark brown dye concentrate is removed as a residue after distilling overhead the uxing oil. Under certain operations the deasphalted tar might be solvent treated while the tar is dissolved in the deasphalting medium. However, in general, it is preferred to remove the light petroleum deasphalting solvent and then to iiux the tar with a relatively light petroleum oil of the desired gravity, preferably in the range from about 27 A. P. I. to 29 A. P. I.

The dark brown dye concentrate of the present invention may be utilized inany oil to impart a green fluorescence thereto. The dye concentrate of the present invention, however, is particularly applicable for imparting a green liuorescence to refined petroleum oils boiling in the lubricating oil range. The amount of dye used may vary considerably and will depend to a large extent upon the character of the oil to which it is added. In general, it is preferred to add from 0.25% to 0.75% and not over 1% of the dye, based upon the volume of oil.

The process of the present invention may be readily understood by reference to lthe following examples which are given for the purposes of illustration.

EXAMPLE 1 A petroleum oil boiling in the range from about 360 F. to 540 F. and having a gravity of about 38 A. P. I. wasv extracted' with sulfur dioxide. The sulfur dioxide extract, ,after removal of the solvent, was cracked under conditions in which a 3'A. P. I. gravity cracking coil tar was produced. The cracking coil tar was deasphalted by diluting with an equal volume of light kerosene having a gravity of about '41 A. P. I. The kerosene was removed from the deasphalted tar by distillation with re and steam. The deasphalted tar was then fluxed with a light parafiinic oil having an A. P. I. gravity of about 28. The mixture was then solvent treated with 100% of phenol under conditions to form a solvent extract phase and a raiiinite phase. The respective phases were separated and the phenol removed. The solventfree raiilnate phase was then distilled under vacuum conditions in order to remove overhead the light tluxing oil and to recover as a residue the dark brown dye concentrate of the present invention.

'Ihe dye concentrate, when added in concentrations of 0.5% and 1.0%, had the following effect upon the characteristics of a reiined Coastal lubricating oil of approximately 570 seconds Saybolt viscosity at 100 F.

The data show that the color of the original oil was darkened by the dye and the cast was improved but the carbon residue was not appreciably increased.

Examens 2 volumes of cracking coil tar having a gravity or about 3" A. P. I. were deasphalted by treating said tar with 75 volumes of light crude naphtha at room temperature, resulting in a yield of 75 volumes of asphalt-tree tar on a solventfree basis.

The asphalt-free tar, after separtion from the asphalt but before removal of the naphtha, was further diluted with 150 volumes of paraiiin gas oil and was then treated with 75 volumes of phenol. The temperature of the treat was approximately F. The raiiinate phase comprising approximately 292.5 volumes was separated from the extract phase of about 82.5 volumes. The raiiinate phase was then vacuum distilled to remove overhead the phenol, naphtha and gas oil and to secure as a residue approximately 39 parts by volume of a dark brown dye concentrate of the present invention.

Blends were then prepared, using various percentages of the dye .concentrate with a refined Colombian and with a reiined Coastal lubricating oil, with the following results:

When viewed under reiiected light the above blended oils had a distinct olive green fluorescence which was superior to the fluorescence of the unblended oils. Furthermore` the blended oils were deep red in color when viewed with transmitted light. It is to be noted that the dye of the present invention improved the cloud and pour characteristics of the oil.

The present invention is not to be limited by any theory or mode of operation, but only by the following claims in which it is desired to claim all novelty in so far as the prior art permits.

We claim:

l. Process for the preparation of an improved petroleum oil dye comprising extracting a petroleum oil boiling in the range from about 360 F. to 540 F. with sulfur dioxide under' conditions to form a solvent extract phase and a ra'mate phase, removing the solvent extract phase, separating the sulfur dioxide therefrom and cracking the extract to produce a cracking coil tar having a gravity in the range from about 2 to 6 A. P. I., deasphalting said cracking' coil tar by the addition thereto of a diluent, separating said deasphalted tar and extracting the same with a selective solvent of the class which has a preferential selectivity for the more aromatic type compounds as compared to the more pararlinic type compounds under conditions to form a solvent extract phase and a rainate phase, separating said raiiinate phase and removing the Asolvent therefrom,"disti1ling said solvent-free rafiinate phase under conditions to remove overhead said diluent and to recover as a residue said improved petroleum oil dye. i

2. Process in accordance with claim 1 in which said diluent is kerosene and in which said solvent is phenol.

3. The process of producing lubricating oil addition-agents having the properties of blending with lubricating oils to impart a deep red color by transmitted light and an olive green fluorescence and to improve the pour and cloud characteristics which comprises extracting a petroleum oil boiling in the range from about 360 F. to 540V F. with liquid sulfur dioxide under conditions to form a solvent extract phase and a .rafnate phase, removing the solvent extract phase, removing the sulfur dioxide therefrom and cracking .the extract to produce a cracking coil tar having a gravity in the range from about 2 to 6 A. P. I., deasphalting said cracking coil tar by the addition thereto of a diluent, separating said deasphalted tar and treating the same with a selective solvent of the class which has preferential solubility for the relatively aromatic type compounds as compared to the relatively parainic compounds under conditions to form a solvent extract phase and a raflinate phase, separating said raffinate phase and removing the solvent therefrom, distilling the said solvent free railinate under conditions to remove overhead said diluent and to recover as-a residue the said lubricating oil addition agent.

4. A process in accordance with claim 3 in which said diluent is kerosene and in which said solvent is phenol.

5. Process for the preparation of an improved petroleum oil dye comprising diluting a deasphalted petroleum oil tar obtained by cracking the extract of a petroleum oil treated with a selective solvent having a preferential selectivity for the more aromatic type constituents as com,- pared to the more paraiiinic type constituents under conditions to form a solvent extract phase and a raiiinate phase and 'having an A. P. I. gravity in the range from about 2 to 6, diluting the said tar with a suitable diluent, extracting the diluted tar with a selective solvent having a preferential selectivity for the morev aromatic type constituents as compared to the more paraiiinic type constituents under conditions to .form a solvent extract phase and a rafnate phase, separating the rafiinate phase and removing the solvent therefrom, then distilling the solvent free raninate phase under conditions to remove 4overhead the diluent and to recover as residue said improved dye.

6. Process in accordance with claim 5 in which the said tar is obtained by cracking a sulfur dioxide extract.

7. Process in accordance with claim 5 in which the`diluent is kerosene' and thel selective solvent for treating the diluent tar is phenol. 

